1. Technical Field
The present invention relates to a toner for developing electrostatic latent images.
2. Description of Related Art
Recently, since an image forming device of an electrophotographic type can be used not only for document printing or simple copying in an office as a general copying machine or a printer but also in the field of producing a printed matter which is used outside the office, specifically, for simple printing of variable information from electronic data, its application area is being broadened even to an on-demand-printing (POD) market, which belongs to an area of simple printing. Thus, in-office power consumption increases as it becomes common in the office where several copying machines or printers are placed.
In the POD market, it is required for the printed matter, not copying action, to have a value. As such, it is required to form a printed matter with high image quality.
In order to obtain a printed matter with high image quality, it is known that reducing particle size of a toner is effective, and various kinds of so-called chemical toners have been suggested in order to achieve it. The chemical toner is related to a method of granulating in an aqueous medium or the like, and thus unlike a pulverization method, it has an advantage that toner particles in a small particle size can be obtained with high homogeneity.
Further, in order to reduce power consumption, increase printing speed, or increase types of an applicable paper, a so-called low temperature fixing technique by which toner images are fixed at a lower temperature than that of a conventional case has been focused.
In response to a demand for such low temperature fixing, various studies have been made. As a technique for achieving the low temperature fixing, a technique for incorporating a crystalline polyester resin into a toner is known.
For example, in Japanese Patent Application Laid-Open No. 2012-8529 (US 2011294062 A1), the inventions that are related to a binder resin consisting of a crystalline resin containing a predetermined polycondensation resin component and a predetermined styrene resin component and an amorphous resin containing a predetermined polyester, and a toner containing a colorant are described.
Further, in Japanese Patent Application Laid-Open No. 2012-63559, the invention that is related to a toner containing crystalline polyester with controlled SP value, dispersant for crystalline polyester, first amorphous polyester, and second amorphous polyester or modified polyester derived from the second amorphous polyester, and also a releasing agent and a colorant is described.